A radio massmedia system using a normal broadcast receiver such as a television, a radio or the like basically provides information through a unilateral or unidirectional communication made from a broadcasting station or a program sponsor (hereinafter called "broadcasting station side") to an audience/listener (hereinafter called "audience side"). It is necessary for the broadcasting station side to continue to send information to many and unspecified persons or parties at all times while whether or not the viewers are watching and listening in fact, remains unknown. Further, the audience side must select necessary information from random and massive amounts of information given by broadcasting. Therefore, the degree of information transfer to the audience side can be actually said low. The broadcasting station side repeatedly sends increasingly massive amounts of information to the audience side to overcome the low degree of information transfer, thereby causing a vicious circle that a further increase in labors or trouble occurs to select information. Thus, the broadcasting station side incurs a result that even when the amount of information to be given is increased, commercial effects which are commensurate with that cannot be achieved.
A broadcast for transmitting a digital data signal using a multibroadcasting radio wave or PCM broadcasting radio wave used for a television and a radio has been recently put to practical use. This type of broadcast is of a system capable of simultaneously transmitting additive information based on the digital data signal together with a general broadcasting program and has a potential that a problem developed due to the unidirection of the aforementioned information transfer can be reduced by using such additive information.
The present invention has been made from the foregoing points of view, and it is an object of the present invention to solve the aforementioned problems developed in radio mass media, i.e., the increase in trouble incident to the selection of information and the decrease in commercial effects due to the reduction in the degree of information transfer by effectively utilizing a multibroadcasting system.